Monday, January 28, 2013

Remember all that electrical work so that we could run off a spare generator if push comes to shove? We had a good week of strong winds, so none of it got tested - until Saturday morning. Saturday morning the Kubota generator tried to run - and shut itself off. Murphy's law of generators is that this sort of thing only happens on a Saturday at 40 below. It's almost never 40 below this high up, but it happened this past weekend.

Rob tried a few more times, got a few readings. He reported that there's nothing wrong with the generator, but it was somehow giving us 20-30 Hz, dipping so low the controller shut it off. Then we dragged out the backup generators and got them hooked up. They were a bear to start, especially when in the "off" position, but start they did - and then they shut off. Each would run for 5-10 minutes, then just quit.

Rob shut off most electric loads, including the heater and we went to town. While there, we went by the generator store and were talked out of buying yet another generator. The guy also gave us the name of his favorite electrician, a guy who promised to come out on a Sunday(!)

Sunday morning we rushed to town before the electric appointment, in search of kerosene heaters and a shower. The shower we got at the Tai Chi center, but our first choice of where to get the heaters didn't pan out. Fred Meyer's sells the kerosene, but not the heaters - they have an aisle full of electric heaters. Running out of time, we went home, with a promise that I would go to town if we found some place selling heaters if none of the generators could be made to work.

Rob recalled that he has yet another generator, but this one has an incompatible plug for our system.

The electrician came, making some crack about us living way out there. He and Rob moved some wires further from the controller and got the Kubota running - and the furnace on before the garage froze. The guy also told us what was wrong with the Hondas. Not only is there a main on-off switch, but there's also a toggle for letting air into the gas tank when it's running. If that is set wrong, they create a vacuum and can't keep enough gas flowing into the engine. It's something he learned about the hard way himself.

Sunday, January 20, 2013

A transfer switch is a handy item. We can now switch from our main generator to a backup generator in case we have problems with the big Kubota. Unless we have a bit of wind, we at most have 48 hours of battery power starting from a full charge.

Square-D 60 amp transfer switch with service cable to connect to a generator with a twist lock connector. The Kubota is rated to 50 amps (6000 watts). There are a couple 1/2 HP motors that need a burst of 1800 watts (15 amps) to get started. The charger is set to 20 amps leaving 30 amps to the house for general use. There is a decent amount of wiggle room for the Kubota. When we are in backup generator mode, we will need to take care not to let any of the 1/2 HP motors kick in unless the backup generator is a good size. We did a small test with one of the Honda 2000's and it promptly shutdown when a motor tried to kick in.

Here is the guts of the power generator side of the Kubota. It is a Stamford generator. The main lines into the house were split between the Kubota and the transfer switch. There is a bit more beefy wires in there now. The Kubota has yet to be tested in this new configuration -- the wiring job looks solid. We have had a bit of wind in the past few days to keep us in good standing.

Wednesday, January 16, 2013

I know there are at least three knitters who might read this, so I thought I'd get this out here. A few months back I had need of a panda pattern for Team Unity in Nerd Wars. I opted to make up my own and I based it on this image. I used gimp:

started from one photo.

cropped the image to just the panda.

drew lines where the front leg is since it’s all basically black/shadow.

scaled the image to be only 20 pixels wide while shrinking it less vertically for a stitch aspect ratio of 5/7.

played with the posterize function a bit, then canceled it.

got out pencil mode with a one-pixel paintbrush and started picking my colors.

The resulting image looked like:

Tiny panda

I scaled it up (using interpolation mode "none" in gimp) and made these mittens using mostly mom's leftovers:

Mittens!

I knit them top-down without rotating the pattern... you can see the result.

Last week I was mulling on the problem of automatically putting black lines around each stitch. I finally got a Python-fu program working within gimp to make:

Printable pattern

I'm happy! Code is at github. This project shows that one nice feature would be to figure out how to make the grid be something other than black. I'm not quite sure how - maybe another day.

By the way, we're home today while someone works on the generator system, making it so we can run the house from a backup generator.

Monday, January 14, 2013

Rob has rigged things so that if the weather service puts out a special
weather alert, he gets email on the next hour. He got one today at 11
AM. By then I had contributed what was needed on yet another colleague's
proposal and was going to dive into some debugging. Anyway, I was
talked into going home while the getting was good. Here's are some
views:

The sun came out while we were in the grocery store. Then we saw this low cloud beneath the dark cloud deck.

Pretty trees in the sun.

Then it started raining and we got a hint of a rainbow.

The view from home, back towards town. By then it was snowing.

We heard a big thump and Rob went out to shovel roof snow off the deck - but most is still up on the roof.

We hope we evicted one of the last gremlins from the generator Sunday. Over the past two weeks a normal generator run would suddenly stop. There haven't been any clues to why it was shutting down other than an "overspeed" error on the generator control box. The last nagging problems to fix are a frequency bounce seen on the generator control and something causing the circulation pump to wink out during the start of a generator run.

The problem we worked on Sunday was the "voltage regulator". (In the voice of McCoy: "I am a computer programmer not a diesel mechanic!"). The engine is up front and it drives a Stamford generator. The only symtom we had was on the generator control panel was that the frequency (Hz) was at times bouncing all over the place (anywhere from 10 to 80Hz). I talk to Obie @ ESI that can service the Kubota and generator systems. The next question is: Does the generator also bounce around speeding up and down? Answer: no (it just runs happily along). Now, the generator has a small bit of history when it was initially installed. There is a claim that the voltage regulator was found bouncing around in the control box (pictured right). This could have very well shorted out some part of the control mechanism. Obie says we should replace the regulator and he also hands me a fuel filter. So, I leave ESI with a fuel filter and a $600 newish voltage regulator. I say newish as the part inside is new, but there is a small amount of dust surrounding the box (well aged?). Sunday was the day for the swap out. Nice warm weather expected with freezing rain (but rain never materialized; so far!). We open up the generator control box. We have three black cables coming in from the bottom right (max 20 Amps). The voltage regulator is at the bottom.The voltage regulator is held to the chassis by three rubber attachments. We have four control circuits on the left. A voltage potentiometer (POT) on the left under the four control circuits. Another POT at the far right controlling stabilization. Jumpers bottom left and bottom right. What could go wrong?

The four control circuits. I was initially worried I would forget the order in which these go back onto the replacement board. BUT, as it turns out looking closer at the wires, they are LABELLED! Yahoo! One was actually a little loose -- we tightened that one a bit.

I manage to get the old regulator off, but I snapped one of the four rubber attachments. Sliding the new regulator on, it seems to be a snug fit with just three. We can live without the fourth until we can hunt down a replacement.

Jumper check! The old board is pictured above. Bottom left there are two jumpers. The new board only has one. I steal a jumper from the old board. The jumpers are snug buggers. The manual says the bottom right jumper selects voltage frequency (50 or 60 Hz), kinda important. The old board is set correctly. The new board is set for 50 Hz. Move the jumper. No problem. Back to the manual and work with the POTs.

The manual says the POTs are factory set. The voltage regulator and stability POT seem to be set lower than the old board. I figure this is OK. The only warning in the manual is not to OVER voltage your system. Looking at data from early in the generator history we seem to be aiming for about 120V to 128V. So, we begin generator testing!

I start and stop the generator several times. The frequency looks great! Nominal (no load) frequency is suppose to be 60 to 63 Hz. The generator control box confirms frequency stability. Our inverter can indicate bad power from the generator (flashing RED LED). The first start we get 96V (too low). Turn the POT 1/8th turn and we get 102V. Turn it 1/4 and we get pretty close 122V. No RED LED. So, we let it run. Electronics can be fascinating at times. Normally voltage is HIGHER on an open circuit than a closed (loaded) circuit. Our inverter switches from BATT to the generator after a certain period has passed with good power detected from the generator. What surprises me is that the voltage goes UP! Nothing bad happens, but we do hit 132V. So, we shut things down. I turn the POT down and start again. Before the inverter kicks in we sit at about 118V. The inverter seems happy about it. The inverter kicks over and we jump to 127V. Its on the high side, but well within the limits of what we saw previously. I'd rather split the difference a bit over the 120V. Over the charge cycle the voltage does back down from the high side to the low side. We also do a check on the frequency under LOAD: still within 60 to 63 Hz, YES! But, we will see. At times the old board would operate fine and act up.

We hope this fixes our mysterious shutdowns. It isn't fun when you have just 48 hours of stored power if your going to have a good generator run next time. We have a backup plan in progress. We are installing a transfer switch so we can hook up a backup generator to keep things running if our big Kubota really goes down. If that happens, we will have to do things manual. It has been good to have the Kubota operating automatically and reliably for the past two years!

Sunday, January 6, 2013

It's been a few weeks since I posted here. Since then we've had two quiet weeks off, one visiting my parents, one here in Fairbanks. One California outing was with my brother and his dog Toby to Sunol park, where dogs can run:

It had rained a lot in the previous days and the trail was very muddy!

Mom had taken a class in "viking knitting", a form of nalbinding with wire. This is my first go at it:

I also showed a couple neighbor kids how to do it. At least one really enjoyed it and was already proudly wearing her necklace!

Back home, the street signs continue to be a challenge if you don't know the area:

Back to work tomorrow and systems will be down for maintenance for two days this week.